Hi ekrolik,
Welcome to the Mattress Forum!.
The closest forum lists to you is the list for the Chicago region in posts #2 and #4 here and for the South Bend / Fort Wayne region in post #4 here but they are a little far from you (although a trip to Quality Sleep / My Green Bedding in Chicago in particular would certainly be worth the drive because they are one of the members of this site and compete well with the best in the industry in terms of their quality, value, service, and transparency).
Because the lists are a fair drive from you I spent a few hours this morning to take a look and make some phone calls around the Valparaiso, IN. area. The better options or possibilities I could see out of about 18 I looked at (subject to the quality/value guidelines here) and the brands they carry that are more likely to be transparent about their materials that I would focus on are …
http://www.bedzzzdirect.com/ Valparaiso, Schererville, IN. Therapedic, Comfort Solutions, US Bedding (Mattress Development Co), mLily. They have latex hybrids, memory foam, and springs.
http://www.bestpricesonbeds.com/ Valparaiso, IN. Sells a wide range of Symbol mattresses and appear to be fairly knowledgeable. They also now have regular hours and are no longer appointment only.
http://www.naturallywoodfurniturecenter.com/ Michigan City, IN. Therapedic.
http://www.mrmattressllc.com/ La Porte, IN. Also carries Symbol with a range of different types of mattresses but no latex on their floor.
http://www.naturallywoodfurniturecenter.com/ De Motte, IN. Therapedic. King Koil, US Bedding.
I talked with all of these and all of them told me that they would call their factory rep to find out any foam quality/density specs that their customers ask for if they don’t have them available in the store.
Phoenix